(1) Field of the Invention
This invention relates to a trailer particularly adapted to move heavy equipment such as forklifts.
(2) Description of the Related Art
Forklifts present a particular problem for transport, particularly those forklifts which are used for heavy warehouse work.
It is not unusual for these forklifts to weigh 20,000 lbs. Typically these forklifts will have extremely low clearance and will be extremely heavy.
Special trailers have been developed or adapted to move these particular vehicles. For example, the trailer built according to VERSCHAGE, U.S. Pat. No. 4,372,572, is used for this purpose. It is noted that the bed can be lowered so that it is very close to the ground in order that the fork lift may be driven onto the bed. The bed can then be elevated above the ground for transportation over the road. These forklifts are frequently used in warehouses which have loading docks elevated up to four or five feet above the roadway. Therefore it is desirable to have a vehicle where the bed may be elevated to such a height.
There is also the problem of performing repairs and maintenance upon forklifts unless a lift rack is available. Because of their extreme low clearance it is difficult, if not impossible to perform even simple maintenance procedures such as changing a fan belt or draining used motor oil without placing them on a rack. As stated before, they are not mobile except on a level warehouse floor and therefore it is necessary to transport these vehicles to a shop with a rack or other location with special equipment before even such maintenance as discussed above can be performed.
SHIELS, U.S. Pat. No. 4,673,328, and RAVEN, U.S. Pat. No. 2,230,014, have disclosed trailers which can be lowered to ground level and elevated above ground level using a U-shaped frame. With a U-shaped frame there exists a problem of locking the bed for a proper height while transporting the load long distances. Also there is a problem of the U-shaped beams or arms spreading apart. A further problem is that the weight on the bed, suspended by the arms of the U-shaped frame, tends to twist the arms because the bed is usually attached at the inside of the frame and the wheels are attached to the outside of the frame. Since the arms extend from the bight of the U at the front of the trailer, this tends to twist the arms so that the wheels move outward.
SHIELS provides for the connection between the bed and the arms by the U-shaped frame which will hold the bed in a desired position and also prevent the arms of the frame from moving apart. However, SHIELS does not provide any solution for the twisting of the arms as the result of the torsion within the arms described above.
Before filing this application the applicant was aware of the following U.S. Patents and also Japanese Patent 244,731 issued in Japan in 1987.
______________________________________ INVENTOR PATENT NO. ISSUE DATE ______________________________________ JARMIN 2,173,277 1939 BIGDEN 3,288,315 1966 MARLETT 4,702,662 1987 LANDOLL 5,013,056 1991 ______________________________________
The above listed are mentioned here only because the applicant believes that an Examiner would be interested in anything reported by an experienced searcher.